In recent years system LSIs having a plurality of circuits embedded therein have been developed rapidly and various apparatuses and methods have been proposed to test such system LSIs.
Tester manufacturers have proposed mixed-signal testers as testers for semiconductor integrated circuits that are provided only for testing system LSIs. Such testers for semiconductor integrated circuits are quite expensive.
For lower cost and higher accuracy, Japanese Patent Laid-Open No. 2002-236150 proposes a device measuring unit (external ancillary equipment for test: Built Off Self Test (hereinafter, referred to as a BOST unit)). Further, a method is proposed to control and test a BOST unit by using a general-purpose personal computer (PC), which is general-purpose computer, a general-purpose EWS (work station), a communication card, and a communication mode converting module instead of an inexpensive tester.
FIG. 2 is a diagram schematically showing the configuration of this kind of conventional ancillary equipment for testing a semiconductor integrated circuit and a testing method. In the conventional ancillary equipment for testing a semiconductor integrated circuit, general-purpose computer constituted of a general-purpose PC or a general-purpose EWS is used as a controller 22 of a BOST unit 21. The controller 22 and the BOST unit 21 are connected to each other via a communication line 23 of typical communication modes of USB, RS232C, IEEE1394, GPIB, LAN, and so on. As an interface on the BOST unit 21, a communication card 24 is provided for each of the communication modes. The BOST unit 21 comprises one or more slots for mounting the plurality of communication cards 24 in a sharing manner and a communication mode converting module 25 for conversion into a dedicated bus mode for the BOST unit 21.
Moreover, a BOST board 26 provided in the BOST unit 21 is constituted of an ADC/DAC measuring section 27, a measurement data memory 28, an analyzing section 29, a control section 30, and a power supply 31. The ADC/DAC measuring section 27 is constituted of a data circuit for generating a digital test signal and supplying the signal to a DA converter of a semiconductor integrated circuit, which is a device to be measured, a testing digital to analog converter (DAC) for converting a digital test signal from the data circuit into an analog test signal and supplying the signal to an AD converter of the device to be measured, and a testing analog to digital converter (ADC) for converting analog test output from the DA converter of the device to be measured into digital test output. The measurement data memory 28 stores digital test output from the AD converter of the device to be measured and digital test output from the testing AD converter. The analyzing section 29 analyzes the digital test outputs stored in the measurement data memory 28 and transmits the analysis result to the general-purpose computer 22 of controller 22.
However, in the conventional ancillary equipment for testing a semiconductor integrated circuit, the BOST unit 21 serving as a device measuring unit includes the communication interface cards 24, the communication mode converting module 25, and the control section 30 as well as the ADC/DAC measuring section 27 and the analyzing section 29. Thus, the BOST unit 21 is increased in size and is not suitable as a test board having a large number of external components with a small space. Further, it is difficult to dispose two or more BOST units 21 near a device to be measured.
In the near future, tests will be necessary for semiconductor integrated circuits such as a system LSI combining more kinds of circuits, and thus higher accuracy and lower cost are demanded. In order to accurately test a number of semiconductor integrated circuits, it is necessary to dispose two or more BOST units 21, each having a measuring section suitable for each semiconductor integrated circuit, near the semiconductor integrated circuit serving as a device to be measured.